Compounds of the formula I, N - oxides, tautomeros and the pharmaceutically acceptable salts of the same that are inhibitors of phosphodiesterase Type 10. Where q is o or s is n or CH x1 x2 is o or s r1 is Y1 - cyc1 R2 is Hydrogen, halogen, etc. it is CYC3 Y3 - R3, R4 is c1-c4 alkyl, etc. y1, y3 is link, CH2, etc cyc1 CYC3 are phenyl etc.Preferred compounds are: 5 - methyl - 3 - (oxetan - 3 - ilamino) - 7 - (pyridin-4-yl) thieno [2,3-d] 4 pyridazin-3 (5H) - One 5 - methyl - 3 - (morpholin-4-yl) - 7 - (pyridin-4-yl thieno [2,3-d]) pyridazin-3 4 (5H) - OneCompuestos de la formula I, los N-oxidos, tautomeros, y las sales farmaceuticamente aceptables de los mismos que son inhibidores de la fosfodiesterasa tipo 10. Donde Q es O o S X1 es N o CH X2 es O o S R1 es Y1-Cyc1 R2 es hidrogeno, halogeno, etc. R3 es Y3-Cyc3, R4 es C1-C4 alquilo, etc. Y1 , Y3 es enlace, CH2, etc. Cyc1 Cyc3 son fenilo, etc. Compuestos preferidos son: 5-metil-3-(oxetan-3-ilamino)-7-(piridin-4-il)tieno[2,3-d]piridazin-4(5H)-ona 5-metil-3-(morfolin-4-il)-7-(piridin-4-il)tieno[2,3-d]piridazin-4(5H)-ona
